Right (but still too short) documentation of the namespaces.
     2 Kruskal's algorithm to find a spanning tree of minimum weight
 
     3 If the graph is not connected, it gives a forest. 
 
     8 #include <union_find.h>
 
    12   template <typename graph_type, typename T>
 
    17     typedef typename graph_type::NodeIt NodeIt;
 
    18     typedef typename graph_type::EdgeIt EdgeIt;
 
    19     typedef typename graph_type::EachNodeIt EachNodeIt;
 
    20     typedef typename graph_type::EachEdgeIt EachEdgeIt;
 
    21     typedef typename graph_type::SymEdgeIt SymEdgeIt;
 
    25     typename graph_type::EdgeMap<T> &weight;
 
    27     //Auxilliary variables
 
    28     typename graph_type::NodeMap<int> component(flowG);
 
    32 	    typename graph_type::EdgeMap<T> & _weight)
 
    39       /*Originally by Misi.*/
 
    42 	NodeMap<graph_type, T> &d;
 
    43 	Node_dist_comp(NodeMap<graph_type, T> &_d) : d(_d) {} 
 
    45 	bool operator()(const NodeIt& u, const NodeIt& v) const 
 
    46 	{ return d.get(u) < d.get(v); }